The incidence of preventable serious injury and death among on-duty firefighters is much higher than in most other occupations. Over 100 firefighters a year are killed in the line of duty, many more in some years. Generally, over 50% of these deaths are from heart attacks due to the high-stress associated with extreme exertion in life-and-death situations. The goal of the proposed work is to develop a novel monitoring system for the fire industry which will transmit vital sign and environmental parameter data from firefighters in a burning building to the safety officer or incident commander on the outside. This will allow the safety officer to detect when a firefighter is becoming dangerously fatigued and to make medically sound decisions about when to rotate personnel, thereby avoiding preventable injury and death. The work will focus on selecting sensors to measure the desired vital signs and environmental parameters, incorporating these sensors into firefighter timeout gear, designing appropriate electronics and processing for these sensors, developing [unreadable] robust telemetry system for reliably transferring data from within a variety of structures, and designing a [unreadable] user-interface which can be easily used by a fire safety officer. A distinguishing feature of Extreme Endeavors is that all of our engineers are also firefighters and/or emergency medical technicians, providing us with a unique perspective on the engineering requirements and tradeoffs for a system such as this. Under Phase I, a proof-of-concept system was constructed that allowed monitoring of heart rate, ECG, ambient temperature, body temperature, and motion detection on a single firefighter inside a bumming structure with 1-foot thick reinforced concrete walls. No system meeting these specifications existed previous to this Phase I project. Under Phase II funding, we propose to broadly extend and enhance the capabilities of the system developed in Phase I. Specifically, we will provide the ability to monitor additional vital signs and environmental parameters, enhance the ability of the units carried by the firefighters to process and analyze data, design an entirely new telemetry system which will function under a broader range of situations, develop a simpler user-interface which is amenable for Use in the fire industry, and work on ruggedizing the system and incorporating the sensors into firefighter turnout gear. [unreadable] [unreadable] [unreadable]